Breathe easier, sulfur dioxide pollution from coal plants in the eastern United States dropped by nearly half compared to 2005 levels, reported a team of researchers in Geophysical Research Letters.
The researchers attributed the drop to the Environmental Protection Agency's Clean Air Interstate Rule. The rule passed in 2005 and called for major reductions in sulfur dioxide pollution.
Sulfur dioxide is a major contributor to acid rain and can cause serious respiratory problems in people, according to the US Agency for Toxic Substances and Diseases Registry. Fossil fuel power plants account for 73 percent of sulfur dioxide emissions in the US, according to the EPA.
"What we're seeing in these satellite observations represents a major environmental accomplishment," said Bryan Bloomer, an Environmental Protection Agency scientist familiar with the new satellite observations, in a press release. "This is a huge success story for the EPA and the Clean Air Interstate Rule," he said.
Major declines were seen around 40 large coal power plants in Alabama, Georgia, Indiana, Kentucky, North Carolina, Ohio, Pennsylvania and West Virginia.
Besides the good news for American lungs and forests, the study introduced techniques that could help pollution monitoring world-wide.
For the first time ever, highly detailed maps of sulfur dioxide releases were made using the Ozone Monitoring Instrument on NASA's Aura satellite. The satellite has been used for less detailed observations of volcanic plumes and highly polluted areas of China.
A mathematical technique by study leader Vitali Fioletov of Environment Canada made the high level of detail possible.
"Vitali has developed an extremely powerful technique that makes it possible to detect emissions even when levels of sulfur dioxide are about four times lower than what we could detect previously," said co-author Nickolay Krotkov of NASA's Goddard Space Flight Center, in a press release.
Using a satellite to measure pollutants opens the way to monitor contamination in areas where ground level monitoring is spotty or non-existent.
"Now that we've confirmed that the technique works, the next step is to use it for other parts of the world that don't have ground-based sensors," said co-author Nickolay Krotkov of NASA's Goddard Space Flight Center. "The real beauty of using satellites is that we can apply the same technique to the entire globe in a consistent way."
Appollo Beach power plant in Appollo Beach, FL. (Wikimedia Commons)
Map of sulpher dioxide emissions created using NASA sattelite images (NASA's Earth Observatory)